Definitely not an expert on carry situations (I live in Canada where carry isn't an option for the average person). I'd always thought the phrase "mexican carry" in common usage meant no holster, behind the hip bone. I guess the phrase originally just meant tucking your pistola in your waistband, wonder if the banditos argued about where the best place to stick it was.
There seems to be some disagreement about what it means now, and whether or not its a good idea. I'd agree that a good holster should offer more protection to the controls of the pistol. I'd also agree that at your side is better than in the front (we're all afraid of the AD in the crotch).
I don't wear baggy pants, and always wear a solid belt. It is very comfortable to simply tuck it in at the hip, slightly canted forward. If I carried, and was in a situation where I had to run, I don't think it would be an issue. Hard to say though since I've never been in that situation.
Moot point from me though, still a Canuck! And my name isn't because I'm necessarily endorsing the method, I just thought it was a funny handle for cowboy action.
To wrap this post up, my opinion is this: in belt at hip is ok (not as secure as a holster obviously), but much better than in front of pants or in small of back. Just my inexperienced opinion.